Quantitative Analysis of Mycophenolic Acid and Metabolites in Serum Using a Single Quadrupole Mass Spectrometer

Significance of the Topic

Mycophenolic acid (MPA) and its glucuronide metabolite (MPA-G) are critical biomarkers for immunosuppressive therapy monitoring. Accurate quantitation in plasma ensures optimal dosing and mitigates adverse effects. High-throughput and selective methods are needed to address limitations of immunoassays, such as cross-reactivity and variability.

Objectives and Overview

This study illustrates a rapid, robust approach for quantifying MPA and MPA-G in serum using a compact single quadrupole mass spectrometer. It aims to deliver high sensitivity, linearity, and throughput with simplified operation, demonstrating applicability for routine therapeutic drug monitoring.

Methodology and Instrumentation

Sample preparation involved protein precipitation with commercial DOSIMYCO reagents and isotope-labeled internal standards ([13C,2H3]-MPA and [13C,2H3]-MPA-G). After vortex mixing and centrifugation, supernatants underwent trap-and-elute separation.
Instrumentation details:

• Liquid chromatograph: Nexera X3 UHPLC system
• Mass spectrometer: LCMS-2050 single quadrupole with DUIS ionization (combining ESI and APCI benefits)
• Columns: DOSIMYCO trapping and analytical
• Mobile phases: DOSIMYCO solvents A and B
• Flow rates: 0.8 mL/min (analysis), 2 mL/min (trap)
• Column temperature: 65 °C
• Injection volume: 10 µL
• MS mode: Selected Ion Monitoring at m/z 338.0 (MPA), 342.0 ([13C,2H3]-MPA), 514.0 (MPA-G), 518.0 ([13C,2H3]-MPA-G)

Main Results and Discussion

Calibration curves exhibited excellent linearity (R2 ≥ 0.9995) across 0.1–50 mg/L for MPA and 1–250 mg/L for MPA-G. The 2-minute per sample run time enabled high throughput. Control samples at low, medium, and high concentrations delivered accuracy within 90–105% and precision (%RSD) below 5%, satisfying bioanalytical method validation criteria.

Benefits and Practical Applications

• Rapid analysis: 2 min/sample accelerates lab workflows
• Cost-effectiveness: single quadrupole MS is accessible for diverse laboratories
• High selectivity and sensitivity: reliable quantitation in complex biological matrices

Future Trends and Potential Applications

Ongoing miniaturization and enhanced ionization techniques will shorten analysis times and further improve sensitivity. Future applications may include multiplexed immunosuppressant panels and point-of-care therapeutic monitoring.

Conclusion

The LCMS-2050 single quadrupole system delivers fast, accurate quantitation of MPA and MPA-G in serum, offering a practical solution for routine therapeutic drug monitoring in clinical and research settings.